to turn the sounds off on telegram, hit the "gear" icon on the bottom, left of center. that takes you to your account settings.
then go into the 2nd submenu from the top: sounds and notifications. you'll see options to turn off notifications at the top of that page. or you can customize them to only happen when it's not the active app, etc.
scroll down for 2 screenshots:
what's great is under the "mute" menu (found by option clicking over a channel) you can customize whether a telegram chat for a crypto is silent or has a specific sound. so you could mute all crypto chats but the one you care about most.